Illuminated microsurgical instrument including optical fiber with beveled end face

ABSTRACT

An illuminated microsurgical instrument includes a microsurgical instrument having a distal tip and an optical fiber for delivering a beam of light to a surgical site. The optical fiber includes a proximal end for receiving a light beam from a light source, and a distal end proximate to the distal tip of the microsurgical instrument for emitting the light beam. The distal end includes a beveled end face either oriented toward or oriented opposite from the distal tip of the microsurgical instrument.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority based on U.S. Provisional PatentApplication Ser. No. 61/483,224 filed May 6, 2011.

BACKGROUND

Various surgical procedures, called vitreo-retinal procedures, arecommonly performed in the posterior segment of the eye. Vitreo-retinalprocedures are appropriate to treat many serious conditions of theposterior segment. Vitreo-retinal procedures treat conditions such asage-related macular degeneration (AMD), diabetic retinopathy anddiabetic vitreous hemorrhage, macular hole, retinal detachment,epiretinal membrane, CMV retinitis, and many other ophthalmicconditions.

A surgeon performs vitreo-retinal procedures with a microscope andspecial lenses designed to provide a clear image of the posteriorsegment. Several tiny incisions just a millimeter or so in length aremade on the sclera at the pars plana. The surgeon inserts microsurgicalinstruments through the incisions, such as a fiber optic light source toilluminate inside the eye; an infusion line to maintain the eye's shapeduring surgery; and instruments to cut and remove the vitreous body. Aseparate incision may be provided for each microsurgical instrument whenusing multiple instruments simultaneously.

During such surgical procedures, proper illumination of the inside ofthe eye is important. Typically, a thin optical fiber is inserted intothe eye to provide the illumination. A light source, such as a halogentungsten lamp or high pressure arc lamp (metal-halides, Xe), may be usedto produce the light carried by the optical fiber into the eye. Thelight passes through several optical elements (typically lenses,mirrors, and attenuators) and is transmitted to the optical fiber thatcarries the light into the eye.

As with most surgical procedures, there is a benefit to minimizing thenumber and size of incisions required to perform the vitreo-retinalprocedure. Incisions are typically only made large enough to accommodatethe size of the microsurgical instrument being inserted into theinterior of the eye. Efforts to minimize the incision size generallyinvolve reducing the size of the microsurgical instrument. Depending onthe size of the microsurgical instrument employed, the incision may besmall enough to render the resulting wound substantially self-healing,thereby eliminating the need to employ additional procedures to closethe incision, such as sutures. Reducing the number of incisions may beaccomplished by integrating various microsurgical instruments. Forexample, the optical fiber may be incorporated into the working end of amicrosurgical instrument. This may eliminate the need for a separateillumination incision, and offers the advantage of directing the lightbeam, together with the microsurgical instrument, onto the target sitethrough a common opening in the sclera. Unfortunately, at least someprior attempts at integrating illuminating optical fibers withmicrosurgical instruments have resulted in a decrease in illuminatingefficiency, or otherwise adversely effected the distribution of lightemitted from the optical fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic illustration of an exemplary microsurgicalinstrument employing an exemplary integrated fiber optic illuminator,shown illuminating an interior region of an eye;

FIG. 2 is a schematic partial cross-sectional view of the microsurgicalinstrument and integrated fiber optic illuminator;

FIG. 3 is a schematic partial cross-sectional view of a distal end ofthe microsurgical instrument and integrated fiber optic illuminatorshown in FIG. 2;

FIG. 4 is a schematic partial cross-sectional view of the distal end ofthe fiber optic illuminator configured to include a beveled end face;

FIG. 5 is a schematic plan view of the fiber optic illuminator shown inFIG. 4;

FIG. 6 is a schematic partial cross-sectional view of the fiber opticilluminator shown in FIG. 4, employing substantially planar beveled endface;

FIG. 7 is a partial cross-sectional view of the fiber optic illuminatorshown in FIG. 4, employing a generally convex beveled end face;

FIG. 8 is a partial cross-sectional view of the fiber optic illuminatorshown in FIG. 4, employing a generally concave beveled end face;

FIG. 9 is a schematic partial cross-sectional view of the distal end ofthe fiber optic illuminator, with the beveled end face arranged to facegenerally away from the microsurgical instrument;

FIG. 10 is a schematic end view of an alternately configured fiber opticilluminator employing multiple optical fibers;

FIG. 11 is a schematic partial cross-sectional view of the fiber opticilluminator shown in FIG. 10;

FIG. 12 is a schematic end view of an alternately configured fiber opticilluminator employing multiple optical fibers; and

FIG. 13 is a schematic partial cross-sectional view of the fiber opticilluminator shown in FIG. 12.

DETAILED DESCRIPTION

Referring now to the discussion that follows and the drawings,illustrative approaches to the disclosed systems and methods aredescribed in detail. Although the drawings represent some possibleapproaches, the drawings are not necessarily to scale and certainfeatures may be exaggerated, removed, or partially sectioned to betterillustrate and explain the present disclosure. Further, the descriptionsset forth herein are not intended to be exhaustive, otherwise limit, orrestrict the claims to the precise forms and configurations shown in thedrawings and disclosed in the following detailed description.

FIG. 1 illustrates an anatomy of an eye 20, which includes a cornea 22,an iris 24, a pupil 26, a lens 28, a lens capsule 30, zonules 32,ciliary body 34, sclera 36, vitreous region 38, retina 40, macula 42,and optic nerve 44. Cornea 22 is a clear, dome shaped structure on thesurface of eye 20 that acts as a window, letting light into the eye.Iris 24, which corresponds to the colored part of the eye, is a musclesurrounding pupil 26 that relaxes and contracts to control the amount oflight entering eye 20. Pupil 26 is a round, central opening in iris 24.Lens 28 is a structure inside eye 20 that helps focus light on retina40. Lens capsule 30 is an elastic bag that encapsulates lens 30, helpingto control the shape of lens 28 as the eye focuses on objects atdifferent distances. Zonules 32 are slender ligaments that attach lenscapsule 30 to the inside of eye 20, holding lens 28 in place. Ciliarybody 34 is a muscular area attached to lens 28 that contracts andrelaxes to control the size of the lens for focusing. Sclera 36 is atough, outermost layer of eye 20 that maintains the shape of the eye.Vitreous region 38 is a large, gel-filled section located towards a backof eye 20 that helps maintain the curvature of the eye. Retina 40 is alight-sensitive nerve layer at the back of eye 20 that receives lightand converts it into signals to send to the brain. Macula 42 is an areain the back of eye 20 that includes receptors for detecting fine detailin a viewed image. Optic nerve 44 transmits signals from eye 20 to thebrain.

With continued reference to FIG. 1, various microsurgical instruments 46may be inserted through sclera 36 into vitreous region 38 whenperforming an ophthalmic surgical procedure, such as a vitreoretinalprocedure. For purposes of this specification, a microsurgicalinstrument 46 refers to any tool sized for insertion through an incisionthat is adapted to perform physical or electromagnetic manipulation ofocular tissue. These may include a variety of surgical instruments, suchas, for example, a vitrectomy probe 48, infusion cannula 50 andaspiration probe 51. Microsurgical instrument 46 may include anintegrated fiber optic illuminator 52 for illuminating an interior ofeye 20.

With reference to FIG. 2, fiber optic illuminator 48 may be opticallyconnected to an illuminator 54 for producing light that may be used toilluminate vitreous region 38 of eye 20 during various intra-opticalprocedures, such as vitreoretinal surgery. Light produced by illuminator54 may be transmitted to the interior region of the eye through anoptical fiber 56. Optical fiber 56 may include a fiber optic connector58 for optically connecting a proximal end 60 of optical fiber 56 toilluminator 54. Fiber optic connector 58 may be configured to releasablyconnect to a correspondingly configured illuminator optical connectoroperably associated with illuminator 54.

Continuing to refer to FIG. 2, optical fiber 56 may have any of avariety of configurations. In the exemplary configuration shown in FIG.2, optical fiber 56 includes an optically transmissive fiber optic core62 surrounded by a cladding material 64 having a low index of refractionrelative to core 62. Fiber optic core 62 may be made of variousmaterials, including, but not limited to, glass and plastics. Opticalfiber 56 may also include additional layers, depending on therequirements of a particular application. For example, optical fiber 56may include a buffer material encasing cladding material 64, as well asan outer protective jacket for shielding the cable's interior componentsfrom damage. A distal end 66 of optical fiber 56 may include an opening68 for emitting light 70 produced by illuminator 54.

Continuing to refer to FIG. 2, illuminator 54 may employ a light source72 for generating light at a particular luminous flux and chromaticity.The light may be emitted over a relatively wide or narrow range ofwavelengths depending on the type of light source employed. Light source72 may employ various light producing technologies, including, but notlimited to, lamp based light sources, such as halogen tungsten lamps andhigh-pressure arc lamps (metal-halides and Xe). Light emitting diodes(LEDs) may also be employed as light source 72. Lasers may also beemployed as light source 72. Lasers are generally capable of producinglight having a relatively high degree of coherence, as compared to otherlight sources, such as LEDs and lamp based light sources. High coherenceenables the emitted light to be focused to smaller spot sizes for moreefficient transmission to optical fiber 56. The ability to focus theemitted light to small spot sizes may enable the use of smaller opticalfibers, such as nano-scaled optica; fibers, which may in turn limit thesize of an incision required to insert microsurgical instrument 46 intoeye 20. Nano-scale optic fibers generally have a diameter (or otherlargest cross-sectional dimension) of less than 100 microns.

Due to the small size of nano-scale optic fibers, it may be possible tointegrate fiber optic illuminator 52 with another surgical instrument,such as microsurgical instrument 46, to reduce the number of surgicalincisions required for inserting surgical instruments during avitreoretinal procedure. Continuing to refer to FIG. 2, microsurgicalinstrument 46 may be suitably connected to a service source 72, forexample, via conduit 74. Service source 72 may be configured to providevarious services used in connection with operating microsurgicalinstrument 46. For example, Service source 72 may provide pressureand/or vacuum for operating microsurgical instrument 46. Vacuum may alsobe provided for aspirating fluids and materials from the interior of eye20. Service source 72 may provide a source of fluids used in connectionwith the surgical procedure.

Microsurgical instrument 46 may have various configurations depending onthe surgical procedure performed. For example, certain ophthalmicsurgical procedures may require the cutting and/or removal of vitreousregion 38, which is a transparent jelly-like material that fills theposterior segment of eye 20. Vitrectomy probe 48 may be used to resectand remove the vitreous region. In one exemplary configuration,vitrectomy probe 48 may include a hollow outer cutting member, a hollowinner cutting member arranged coaxially with and movably disposed withinthe hollow outer cutting member, and a port extending radially throughthe outer cutting member near a distal end 76 thereof. Vitreous region38 is aspirated into the open port, and the inner member is actuated toclose the port and sever the vitreous material, which may then beaspirated away through conduit 74. The mechanism for actuating thehollow inner member may be enclosed within a housing 78, which may alsofunction as a handle for grasping microsurgical instrument 46.Microsurgical instrument 46 may also be configured as infusion cannula50 for delivering a fluid to the interior of eye 20. The fluid may bedelivered to infusion cannula 50 through conduit 74. Conduit 74 may alsobe used to connect microsurgical instrument 46 to a vacuum source, forexample, when configuring microsurgical instrument 46 as aspirationprobe 51.

Referring to FIG. 3, in certain applications, it is generally desirablefor light beam 70 emitted from fiber optic illuminator 52 to have arelatively wide angular distribution to enable illumination of acorresponding wide surgical field within eye 20. However, a portion ofthe light beam 70 emitted from optical fiber may be either absorbed orreflected from an adjacent outer surface 80 of microsurgical instrument46, depending on the positioning of distal end 66 of optical fiber 56relative to distal end 76 of microsurgical instrument 46. It may notalways be desirable, however, to position distal end 66 of optical fiber56 proximate to end 76 of microsurgical instrument 46. Positioningdistal end 66 of optical fiber 56 a distance “D” from distal end 76 ofmicrosurgical instrument 46 may, however, adversely affect theilluminating efficiency of fiber optic illuminator 52, particularly ininstances in which a measurable portion of the emitted light is absorbedby outer surface 80 of microsurgical instrument 46.

Referring to FIGS. 4 and 5, to help avoid a distal tip of microsurgicalinstrument 46 interfering with the propagation of light beam 70 emittedfrom optical fiber 56, distal end 66 may be provided with a beveled endface 82 arranged at an oblique angle relative to an optical axis 84 ofoptical fiber 56. For purposes of this specification, “beveled end face”need not refer strictly to a flat beveled surface but rather may includeany configuration wherein a distalmost end face is arranged so that thesurface normal, i.e., the axis perpendicular to the surface, is deviatedto one side of the optical axis 84 over the majority of the end face,making the distalmost end face asymmetrical relative to the opticalaxis. When the beveled end face 82 is said to “point” or to be“oriented” toward a certain direction, this refers to the side of theoptical axis 84 toward which the beveled end face 82 is asymmetricallydeviated. Inclining end face 82 relative to optical axis 84 generallyresults in light beam 70 approaching beveled end face 82 at an obliqueincidence angle relative to the surface normal at the point ofincidence. The transition between the two different refractive indicescauses the light to refract as it transitions the interface betweenoptical fiber 56 and vitreous region 38 of eye 20, thereby deflecting apropagation path 86 of light beam 70 away from optical axis 84 ofoptical fiber 56. The amount of refraction may be approximated usingSnell's law, which provides:

n1*Sin(↓₁)=n2*Sin(↓₂)

where:

-   -   n1 is the refractive index of fiber optic core 62    -   n2 is the refractive index of vitreous region 38    -   ↓₁ is the propagation angle of light beam 70 within fiber optic        core 62        -   ↓₂ is the propagation angle of light beam 70 within vitreous            region 38,        -   where ↓₁ and ↓₂ are both measured relative to the surface            normal of the beveled end face 82.

Because the index of refraction of the vitreous region is lower thanthat of the fiber optic core, the light beam 70 will tend to berefracted away from the surface normal of the beveled end surface 82,viz., ↓₂>↓₁. The angular distribution of the rays in light beam 70 asthe rays travel through the optical fiber 56 will therefore produce anangular distribution in the emitted light beam 70, which will bepreferentially shifted away from the optical axis 84 of the opticalfiber 56.

While beveled end face 82 is illustrated on an optical fiber 56 ofuniform diameter, beveled end face 82 may also be used on a fiber opticwith a tapered distal tip that narrows to a smaller width along a paththat may includes curved or straight segments as the fiber optic extendstoward the distal tip. In particular embodiments of the tapered distaltip, the cladding may also be removed. The tapered distal end provides awider angular distribution, which may advantageously be combined withthe deflection produced by the beveled end face 82 to produce a widerillumination beam from the fiber optic selectively directed in aparticular direction around the tip of the surgical instrument.

The deflection of light beam 70 relative to microsurgical instrument 46is at least partially dependent on the orientation of beveled end face82 relative to microsurgical instrument 46. For example, orientingbeveled end face 82 to point toward microsurgical instrument 46, such asshown in FIG. 4, tends to shift propagation path 86 of the light beamaway from microsurgical instrument 46. On the other hand, orientingbeveled end face 82 to point away from microsurgical instrument 46, suchas shown in FIG. 9, tends to shift the propagation path 86 of light beam70 toward microsurgical instrument 46. Referring to FIG. 9, fiber opticilluminator 52 is shown with beveled end face 82 oriented to facegenerally away from microsurgical instrument 46. This arrangementgenerally results in propagation path 86 of light beam 70 being shiftedtoward microsurgical instrument 46. Thus, this arrangement increases,rather than decreases, the amount of light reflected from microsurgicalinstrument 46. A wider dispersion of light emitted from optical fibermay be obtained by enhancing the reflectivity of outer surface 80 ofmicrosurgical instrument 46. Light emitted from optical fiber 56 may bereflected from surface 80 of microsurgical instrument 46 to provide abroader distribution of light within an interior region of eye 20.

FIGS. 6-8 are partial cross-sectional views taken through beveled endface 82 (see FIG. 4) along a perspective generally parallel to end face82. Beveled end face 82 may include a variety of surface contours. Forexample, FIG. 6 shows beveled end face 82 configured to include a planarsurface. Beveled end face 82 may alternatively be configured to includea generally convex surface contour, such as shown in FIG. 7. Beveled endface 82 may also have a generally concave configuration, as shown inFIG. 8. These are merely a few examples of the various surface contoursthat may be employed with beveled end face 82. In practice, othercontours may also be employed to accommodate design and performancerequirements of a particular application.

Referring to FIGS. 10-13, fiber optic illuminator 52 may be configuredto include multiple bundled optical fibers 56 surrounding a distal tipof a microsurgical instrument 46. FIG. 10 shows an exemplary arrangementincluding four optical fibers 56 bundled together. Each optical fibermay include a beveled end face 82 for selectively controlling apropagation path of emitted light. In the exemplary arrangementillustrated in FIGS. 10 and 11, beveled end face 82 of optical fibers 56positioned at opposite corners of the cable bundle are shown oriented soas to generally face one another. This particular arrangement tends toincrease the dispersion of the emitted light by shifting propagationpath 86 of light beam 70 outward from a center axis 88 of the bundle.

FIGS. 12 and 13 show an exemplary optical fiber bundle including sevenoptical fibers 56. The optical fibers are shown arranged generally in ahexagonal pattern, with six optical fibers positioned around a centeroptical fiber. Each of the outer optical fibers 56 may include a beveledend face 82 for selectively controlling a propagation path of emittedlight. The single center optical fiber 56 in this exemplaryconfiguration does not include a beveled end face. Beveled end faces 82of the outer optical fibers 56 may be oriented so as to generally pointradially inward toward a center of the optical fiber bundle. Thisparticular arrangement tends to increase the dispersion of the lightemitted from the outer optical fibers by shifting propagation path 86 oflight beam 70 outward from the center of the optical fiber bundle.

The distal end of the entire bundle is placed proximate to a distal tipof a microsurgical instrument 46. The central fiber optical cable and/orthe optical fibers that are more remote from the distal tip of themicrosurgical instrument 46 can have a flat surface so that thepropagation path of light emitted from the center optical fiber tends tocoincide with optical axis of the optical fiber. In such embodiments,light emitted from the center optical fiber 56 may fill a light voidthat may exist between the light beams emitted from the surroundingouter optical fibers 56, while still allowing the overall amount ofreflected light from the distal tip of the microsurgical instrument 46to be reduced by the orientation of the closest optical fibers 56. Forexample, if the distal tip of the microsurgical instrument 46 isreflective, then the depicted orientation of the beveled end faces 82can advantageously provide additional illumination through reflection,as previously illustrated in FIG. 9. Alternatively, in the case of anon-reflective tip of microsurgical instrument 46, the beveled end faces82 could be reversed to point toward the distal tip of microsurgicalinstrument 46, preferentially shifting the illumination away from thedistal tip of microsurgical instrument 46, as illustrated in FIG. 4. Inyet another alternative embodiment, the optical fibers 56 can be placedin a similar configuration as illustrated in FIGS. 10-13, but centeredaround the distal tip of microsurgical instrument 56, so as to produceillumination from multiple optical fibers 56 around the microsurgicalinstrument 56.

It will be appreciated that the exemplary surgical illumination systemdescribed herein has broad applications. The foregoing configurationwere chosen and described in order to illustrate principles of themethods and apparatuses as well as some practical applications. Thepreceding description enables others skilled in the art to utilizemethods and apparatuses in various configurations and with variousmodifications as are suited to the particular use contemplated. Inaccordance with the provisions of the patent statutes, the principlesand modes of operation of the disclosed surgical illumination systemhave been explained and illustrated in exemplary configurations.

It is intended that the scope of the present methods and apparatuses bedefined by the following claims. However, it must be understood that thedisclosed surgical illumination system may be practiced otherwise thanis specifically explained and illustrated without departing from itsscope. It should be understood by those skilled in the art that variousalternatives to the configuration described herein may be employed inpracticing the claims without departing from the scope as defined in thefollowing claims. The scope of the disclosed surgical illuminationsystem should be determined, not with reference to the abovedescription, but should instead be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. It is anticipated and intended that futuredevelopments will occur in the arts discussed herein, and that thedisclosed systems and methods will be incorporated into such futureexamples. Furthermore, all terms used in the claims are intended to begiven their broadest reasonable constructions and their ordinarymeanings as understood by those skilled in the art unless an explicitindication to the contrary is made herein. In particular, use of thesingular articles such as “a,” “the,” “said,” etc. should be read torecite one or more of the indicated elements unless a claim recites anexplicit limitation to the contrary. It is intended that the followingclaims define the scope of the device and that the method and apparatuswithin the scope of these claims and their equivalents be coveredthereby. In sum, it should be understood that the device is capable ofmodification and variation and is limited only by the following claims.

1. An illuminated microsurgical instrument comprising: a microsurgicalinstrument having a distal tip; and an optical fiber for delivering abeam of light to a surgical site, the optical fiber including a proximalend for receiving a light beam from a light source, and a distal endproximate to the distal tip of the microsurgical instrument for emittingthe light beam, the distal end including a beveled end face eitheroriented toward or oriented opposite from the distal tip of themicrosurgical instrument.
 2. The illuminated microsurgical instrument ofclaim 1, wherein the beveled end face bisects the optical axis.
 3. Theilluminated microsurgical instrument of claim 1, where the beveled endface is a substantially planar surface.
 4. The illuminated microsurgicalinstrument of claim 1, wherein the beveled end face includes a generallyconvex surface contour.
 5. The illuminated microsurgical instrument ofclaim 1, wherein the beveled end face includes a generally concavesurface contour.
 6. The illuminated microsurgical instrument of claim 1,wherein the microsurgical instrument includes a proximal end, and thedistal end of the optical fiber is arranged between the distal tip andthe proximal end of the microsurgical instrument.
 7. The illuminatedmicrosurgical instrument of claim 6, wherein the microsurgicalinstrument includes an exterior reflective surface proximate to thedistal tip of the microsurgical instrument, and the beveled end face isoriented away from the distal tip of the microsurgical instrument. 8.The illuminated microsurgical instrument of claim 7, wherein the beveledend face is arranged at an oblique angle relative to an optical axis ofthe optical fiber and a longitudinal axis of the microsurgicalinstrument.
 9. The illuminated microsurgical instrument of claim 1,wherein the optical fiber is a first optical fiber, and the illuminatedmicrosurgical instrument further comprises at least one additionaloptical fibers, wherein the distal end of each additional optical fiberincludes a beveled end face arranged at an oblique angle relative to anoptical axis of the respective optical fiber.
 10. The illuminatedmicrosurgical instrument of claim 9, wherein the first optical fiber andthe additional optical fibers are arranged around the distal tip of themicrosurgical instrument.
 11. The illuminated microsurgical instrumentof claim 1, wherein the optical fiber is one of a bundle of opticalfibers around a central optical fiber.
 12. The illuminated microsurgicalinstrument of claim 1, wherein the distal end of the optical fiber istapered.